Optical code scanners are used in a wide variety of applications that rely on reading information stored in optical codes. Industries such as retail, airline, self-service, automotive, parcel delivery, pharmaceutical, healthcare and others use optical codes to provide inventory control, customer identification, product identification, item tracking, security and many other functions. A bar code is a type of optical code in wide use and a bar code scanner is a type of optical code scanner configured to read bar codes. A typical bar code is comprised of a number of bars separated by spaces. Information is encoded in a bar code by varying the width of the bars and spaces. When a bar code is placed within the field of view of a bar code scanner, the scanner will detect and decode the bars and spaces comprising the bar code to retrieve the information encoded wherein. This operation is also known as scanning or reading a bar code. The information encoded on a bar code is usually a sequence of numeric or alphanumeric symbols (e.g., a Universal Product Code (UPC) or European Article Number (EAN)).
The field of view for a bar code scanner is defined as a three dimensional area of space wherein the bar code scanner can reliably detect and read a bar code that passes through the area of space. The field of view for a bar code scanner has a height, width and depth dimension. The depth is commonly referred to the depth of field for a bar code scanner. It is desirable to have a large depth of field because it increases the total volume of space that makes up the field of view, which means more space can be reliably scanned for a bar code.
Bar code scanners that read bar codes by capturing and processing an image of the bar code is called an image scanner. One technique for increasing the depth of field for an image scanner is to reduce the size of the optical aperture in the scanner, however this also reduces the amount light available for capturing an image of a bar code. The reduced light intensity increases the signal to noise ratio making it more difficult to detect and read a bar code. At some point, the bar code cannot be reliably read.
Therefore, it would be desirable to provide an apparatus, system and method that among other things, provides for increasing the depth of field without the above limitations.